The invention relates generally to seals, and, more particularly to a seal which is capable of being pressurized and which is used for the gap between a reciprocating rod and a housing surrounding the rod. The seal is comprised of a dynamically balanced sealing ring of an elastomeric material, which is capable of being inserted into the housing and which is provided at a pressurized end with at least one sealing lip to engage the rod. At the opposite end, the seal has a recess that opens toward the rod and into which is inserted a guide ring comprising a tough, hard polymer material.
Such a seal is disclosed by the German Patent DE-PS 32 45 338, corresponding to U.S. Pat. No. 4,553,761 to Blesing et al., issued Nov. 19, 1985. The disclosure of U.S. Pat. No. 4,553,761 is hereby incorporated by reference into the present specification. In that prior art seal, a back-up ring 8 consisting of tough, hard plastic has a profile shaped to fit in a recess of a sealing ring S. The back-up ring 8 is made available to the user independently of the actual sealing ring, thus making it more difficult to assemble such a seal.